The trader is a good place to get some rare items. He never stays in one place for too long nor do you have any control over what you can get from this guy but it’s a good idea to buy rare materials from him if he has it even if you don’t think that you need it right now. Salvaging items that are valued by the trader will be a good endeavor since you’ll be able to replace it for even hard to find materials that will help upgrade your shelter or help you craft some important items.
One thing that players need to keep in mind when trading is that they need to raise their trust level and reputation. The fastest way to raise your reputation with The Trader is simply to stuff from his selection which increases every time you do so. The trader appears four times a day at random intervals and stays in the base for a limited amount of time. If you’re not playing actively but want to check the trader, it may be a good idea to check your phone every other hour.